A device for parallel image inspection and color regulation of a printed product, which is produced in a printing press with at least one printing group, is known from DE 43 21 177 A1. An image detection arrangement is provided, which forwards image data from the printed product to a computer arrangement. The image detection arrangement consists of one or of several measuring modules, each of which scans a defined image area of the printed product, and of at least one associated receiving device, which creates the image data and which preferably is spatially separated from the measuring modules. The measuring modules and the at least one receiving device are connected with each other by at least one image conductor. A register sensor is also provided, and by the use of which, a register measurement can be performed at the imprinted printed product.
A color registration system for a printing press is known from EP 0 598 490 A1. A computer, with a camera or with a group of cameras, determines an erroneous alignment of colors of a printed product by comparing an actual image with a stored reference image, and, by the use of a printing control, aligns longitudinal, transverse and rotary positions of cylinders of a printing press in relation to a web, which web is moved through the printing press and is to be imprinted. The alignment is done, in such a way that the cylinders create a multi-color image with colors which are correctly aligned with each other.
A device and a method for the register-maintaining matching of printing cylinders of a web-fed rotary printing press is known from EP 0 882 588 A1. A first cylinder, which is imprinting one side of the web, is driven by a first motor, and a second cylinder, which is also imprinting the same side of the web, is driven by a second motor. The angular position of the second cylinder is matched by a regulator to maintain registration with the first cylinder. Register markings, which are imprinted on the web by the cylinders, are recorded by a sensor that is arranged downstream of the last cylinder in the production direction, which sensor may be, for example, a CCD camera. The register markings are evaluated as guide values for the regulator by the use of characteristic lines.